Is there an electrician in the house?

[Clan Delaney]

Here I am getting ready to install some recycled lights into the new shack, and I'm running into the same electrical problems that have confounded me for years. Maybe someone can shed some light on them for me.

I am trying, once and for all, to comprehend Volts, Watts and Amps. Here's how I understand it: Volts are a measure of electrical pressure, the force the pushes electrons through the lines. Fine. Amps are a measure of current, or the flow rate of electrons through a line. Fine again. I think it's the Watt that gets me every time. A Watt is a measure of electrical power, or work done - Amps multiplied by Volts (Watts=Amps*Volts).

I have a power supply for the LED lights I'm looking to install, it's from the original installation. It's listed as a 12V/60W device. What exactly does that 60W rating mean? If I hooked a 15 watt bulb to it, would the bulb burn out? Or does it mean that I could fully power 4 of those 15 watt bulbs (15*4=60 watts)? In the end, I'm wondering if I could power these lights with a wall adapter type power supply. Problem is... their output is measured in Amps, not Watts!

Grrrrrr. Do. Not.... Understand.

[lpakiz]

Match the power supply VOLTS with the VOLT requirement of the load. The amps will take care of themselves.
12 volt car battery==12 volt charger.
120 volt light bulb requires 120 volt supply--doesn't matter about the wattage rating of the bulb, except---

It matters that the amps/watts requirement doesn't exceed the ability of the supply (wire size/circuit breaker/fuse capacity)(or the size of the transformer) to supply those watts.

One 100 watt light bulb in your dining room requires slightly less than 1 amp
(100 watts divided by 120 volts equals about .9 amps)
and your wiring/circuit breaker can safely supply 15-20 amps usually. So, your wiring supply in your dining room could safely supply about 15 of those 100 Watt bulbs (volts X amps =watts) )(wire size/circuit breaker size)
Your 60 watt power supply can support 4 of those 15 watt loads. Remember, the voltage must match and you can't exceed the watts. Hope this helps....

[Haynes Forest Products]

Putting the 15 watt bulb will not burn it out its rated for 60 watts so 4 bulbs at 15 each is ok. The problem with low voltage is they dont like to be under powerd so if you put (10) 15 watt bulbs in the circuit they will be dim and burn out. When we do low voltage landscape lights we have to do calculations on the resistance up to the first light in a circuit and then put that wattage bulbs in. Putting a light rated at 10 amps on a 20 amp circuit will not hurt the light putting 10 of them will only cause them to run at lower amps like from a dimmer and then as the resistance builds it will trip the breaker.

[brookledge]

Watts= Volts X Amps
Amps= Watts/ Volts
Volts= Watts/ Amps
So your power supply that is 12 Volt and 60 Watts will be pushing 5 amps
Not sure if thats what you are looking for
Keith

[Clan Delaney]

I'm gonna think out loud here...

Each LED module consumes 1 watt (they're strung together light x-mas lights). So, I could feasibly sting a maximum of 60 of these modules together (60 watts output from supply, 60 watts consumed by the lights) not accounting for losses to resistance in the wires.

Apparently they can handle a 5 amp current if that's what the power supply is putting out. So if I have a wall adapter type power supply that's listed as 12V, 500 milliamps (.5 amps) it's power output would be 6 watts, and I could safely light as many as 6 of the LED modules with it.

Understand much better now.

[HHM-07]

Clan

Is your device a transformer or a converter?? Usualy low voltage items are converted to dc current, reason is for voltage stabilty your 120 volt house ac current can vary as much as 10 volts or more at any givenn time therefore not good for low voltage items. question ? are these lights going to give you ample light, i would guess not.

[Clan Delaney]

Clan

Is your device a transformer or a converter?? Usualy low voltage items are converted to dc current, reason is for voltage stabilty your 120 volt house ac current can vary as much as 10 volts or more at any givenn time therefore not good for low voltage items. question ? are these lights going to give you ample light, i would guess not.

Good call on the AC - DC. I was talking about a converter. The one I have in front of me converts 120VAC to 12VDC.

Dick, these lights will blind you. I'm barely exaggerating. They came from a commercial sign installation. Bright enough for you to see that sign from the highway. Incredible technology.

[lpakiz]

Clan,
If you need more then the 5 amps that the power supply can give, consider using a 12 volt battery charger. Most are at least 10 amps--many are more.
They will produce more than 12 volts (usually around 14 or so) so your lights would be a bit brighter than designed for, but plenty of amps.
I am also not sure if the over-voltage thing would hurt the LED lights. Car headlights and tail light bulbs are designed to operate on the higher voltage. Plus you can charge the tractor or 4-wheeler batt when ya need to.

[Mac_Muz]

if you run a battery charger to a bigger car battery, and run anything else you want it would just need one 110 ac outlet somewhere you can reach with a cord...

If you can't reach with a cord you could still run a battery for a long time. You would need to re-charge the battery after you used it at some point.

I forgot what the Amp Hour rating a car battery is... Smaller batterys like in a motorcycle are rated in Amp Hours, commonly some are 18 Ah, where you can run 1 amp 18 hours and or 18 amps 1 hour. Any car battery will last many more hours.

[maple flats]

Use a deep cycle battery such as one made for an electric trolling motor. They are designed to be discharged and then recharged. On a car battery the plates are thinner and do not like deep discharging, a car battery is designed to give a lot of power at once to start the car and then immediately be recharged. These are by design and not just how people use them. There is good reason for the different labels on the batteries. Just buy one made for deep cycle. A charger on line with a car battery however would do as well, but do not run a car battery down low and then recharge, that will make a short life for the battery.

[Johnny Cuervo]

I wouldn’t run LEDs much over there rated voltage. You can run as many as you want as long as the sum of all lights, current (amps) or wattage, does not exceed the current or wattage rating of your adaptor or transformer.
The little plug in transformers 120-12v (we call them wall warts) will over heat and burn up if you try to draw more current than rated. I would be a little careful of using a battery charger, most are unregulated and un filtered. Depends on the requirements of your LED display. Are there specs on your LEDs?

[PerryW]

I am trying, once and for all, to comprehend Volts, Watts and Amps. Here's how I understand it: Volts are a measure of electrical pressure, the force the pushes electrons through the lines. Fine. Amps are a measure of current, or the flow rate of electrons through a line. Fine again. I think it's the Watt that gets me every time. A Watt is a measure of electrical power, or work done - Amps multiplied by Volts (Watts=Amps*Volts).

you are correct

I have a power supply for the LED lights I'm looking to install, it's from the original installation. It's listed as a 12V/60W device. What exactly does that 60W rating mean?

It means the power supply will power up to 60 watts worth of power at 12 volts



If I hooked a 15 watt bulb to it, would the bulb burn out?

No, as long as the 15 watt bulb was rated at 12 volts (I am assuming here that the LED lights and the power supply are DC)


Or does it mean that I could fully power 4 of those 15 watt bulbs (15*4=60 watts)?

You are correct.


In the end, I'm wondering if I could power these lights with a wall adapter type power supply. Problem is... their output is measured in Amps, not Watts!

Probably not, unless the Wall adapter produces 12 volts DC


Each LED module consumes 1 watt (they're strung together light x-mas lights). So, I could feasibly sting a maximum of 60 of these modules together (60 watts output from supply, 60 watts consumed by the lights) not accounting for losses to resistance in the wires.


I believe you are correct here.

Apparently they can handle a 5 amp current if that's what the power supply is putting out.

No. The only thing you have to worry about is that you have 12 volts DC. The 5 amp rating is just a MAXIMUM. If you just run a few LED lights, the current draw will be much less than 5 amps


So if I have a wall adapter type power supply that's listed as 12V, 500 milliamps (.5 amps) it's power output would be 6 watts, and I could safely light as many as 6 of the LED modules with it.

Yes as long is it is DC (I am assuming that the LED lights are 12 Volts DC)